Numerous rotary object feeders are known. For example, U.S. Pat. No. 4,518,301 issued May 21, 1985 to R.A. Jones & Co. Inc., discloses an orbital feeder suited for picking up folded cartons from a storage magazine and transporting them to a conveyor, where they are released.
The difficulties with rotary feeders are numerous. The objects to be picked up, such as folded cartons in a magazine, are stationary. It is therefore not possible to simply wipe past the cartons with a pick-up member, typically a suction cup, rotating past the object, with any degree of reliability. Accordingly, a solution to overcome this problem is to alter the path of the pick-up members so that they make contact with the object as they are travelling in a direction generally perpendicular to the plane of the cartons. Rotary carton feeders implementing this solution are known, and incorporate suction cups used as pick-up members mounted on planetary elements. The suction cups move along a hypocycloidal path, and will pick-up objects at points along their path where the suction-cups are travelling in a direction which is perpendicular to the objects. However, because the additional rotation of a planetary element, the perpendicular movement may be somewhat abrupt. Additionally, the object to be picked up is rotated about an additional axis, which may significantly increase the net velocity of the object at certain points along its path. Accordingly, object feeders using this solution do not lend themselves to operation at high speeds. Furthermore to achieve the desired movement, the object is rotated inwardly toward a central axis. This restricts the size and number of objects that can be handled simultaneously by the object feeder.
Moreover, conventional rotary feeders generally use pick-up members that are mechanically linked to the rotation of the feeder. Camming mechanisms, in combination with mechanical air valves, for example, may be used to provide air to suction cups of a feeder, as the feeder rotates. These mechanical arrangements are quite inflexible. They do not allow for the dynamic adjustment of pick-up and drop-off locations around the periphery of the feeder. Moreover, they do not allow adjustment of the release of picked-up objects in response to operating conditions, such as the speed of rotation of the carrier.